Safety switch lock



y was w. HANKE ETAL 3,384,722

SAFETY SWITCH LOCK Filed Feb. 28, 1967 INLEAITQ R BY-fif/ $771.04

ATTUR EY f H J.

United States Patent -O 3,384,722 SAFETY SWITCH LOCK Walter Hanke,Sande-Neufeld, and Wolfgang Klingner, Grafschaft, Germany, assignors toOlympia Werke Filed Feb. 28, 1967, Ser. No. 619,432 Claims priority,applicatitn6gsermany, Mar. 8, 1966,

10 Claims. (Cl. 200-50 ABSTRACT OF THE DISCLOSURE Background of theinvention Safety switch locks are known which interrupt a circuit when aclosure is opened, particularly, it is known to provide means forinterrupting the circuit of the drive motor of an electric typewriterwhen the top cover of the typewriter, or of an accounting or otherbusiness machine, is opened. However, the safety locks according to theprior art are rather complicated and consist of a g at many parts sothat the cost of manufacture and assembly is high.

Summary of the invention It is the main object of the invention toprovide a safety switch lock which will automatically lock the mainswitch of an apparatus in a circuit breaking position when a a closureof the apparatus is opened and permits access to electric circuit partsof the apparatus.

Another object of the invention is to automatically shift the mainswitch of an apparatus to a circuit breaking position when a closure isopened.

With these objects in view, the present invention relates to a safetyswitch lock having locking means controlled by a closure to lock themain switch of an apparatus in a circuit breaking position when theclosure is opened, and to first move the main switch to the circuitbreaking position if it is in a circuit making position when the closureis opened.

One embodiment of the invention comprises a casing, for example atypewriter casing, having closure means, for example the top cover of atypewriter, movable e tween a first closed position and a second openposition; switch means mounted on the housing and having an actuatormovable between a first circuit making position and a second circuitbreaking position; locking means connected with the closure means formovement therewith to first and second positions and having lost motioncoupling means in the form of a pin and slot connection with theactuator; and biasing means for moving the locking means from the secondposition to a locking position locking the actuator.

Due to the lost motion coupling means, the actuator remains in thecircuit breakingposition when the locking means and closure means moveto the second positions, but if the actuator is in the circuit makingposition, it is coupled by engagement of a pin on the actuator with theend of a slot in the locking means and is moved to the circuit breakingposition when the closure is opened.

The slot of the locking means has a transverse locking slot portionpermitting movement of the locking means to the locking position only ifthe actuator is in the 3,384,722. Patented May 21, 1968 circuit breakingposition, or has been shifted to the circuit breaking position by thelocking means.

In the preferred embodiment of the invention, the locking means is anelongated locking member mounted on a pivot means of the housing forlongitudinal movement between the first and second positions, and forturning movement between the second and locking positions. Aspring'urges the locking member to follow the opening movement of theclosure, which is possible due to the provision of a guide slot in thelocking member receiving the pivot means and permiting longitudinal andturning movement of the locking member.

The novel features which are considered as characteristic for theinvention are set forth in particular in the appended claims. Theinvention itself, however, both as to its construction and its method ofoperation, together with additional objects and advantages thereof, willbe best understood from the following description of specificembodiments when read in connection with the accompanying drawings.

Brief description of the drawing FIG. 1 is a fragmentary elevation,partially in section, illustrating a safety switch lock of an electrictypewriter in an operational position in which the closure of thetypewriter is closed, and the switch is in a circuit breaking position;

FIG. 2 is a fragmentary elevation corresponding to FIG. 1, butillustrating the switch in the circuit making position; and

FIG. 3 is a fragmentary elevation corresponding to FIGS. 1 and 2, andillustrating the top cover of the typewriter in an open position, andthe switch locks in the circuit breaking position.

Description of a preferred embodiment Referring now to the drawing, thehousing of a typewriter or like machine, has lateral walls 1, one ofwhich is illustrated. Housing wall 1 carries a fixed pivot passingthrough an elongated guide slot 3a provided in a slanted end portion ofa locking means 3 which has a projection 30 abutting the closure or topcover 5 of the typewriter under the action of a spring 4 which issecured to locking means 3 and to a transverse lug 1a on housing wall 1.When closure 5, which is only partially shown, is opened, locking means3 is urged by spring 4 to follow closure '5 while projection 30 slideson the same until further movement with closure 5 is prevented by theengagement of pivot means 2 with one end of guide slot 3 in the positionof FIG. 3.

Housing wall 1 carries a cover plate 6 on a pair of brackets 6b whichhas a slot 60 having an end bounded by an edge 6d. Locking means 3 is afiat locking bar aligned with slot 6c, but in the positions shown inFIGS. 1 and 2, the end of locking bar 3 slidingly abuts the bottom faceof cover plate 6 under the action of spring 4 which tends to turn thelocking bar 3 in counterclockwise direction. However, when due to theopening of closure 5, locking bar 3 is moved by spring 4 to the positionshown in FIG. 3, the end of locking bar 3 arrives at the edge 6d of theslot or cutout 60 so that spring 4 can turn locking bar 3 about pivotmeans 2 to a position located in slot or cutout 6c and being lockedagainst movement to the right as viewed in the drawing by the edge 6d,while being also locked against movement to the left by pivot means 2since the same is located in the end of guide slot 3a.

A main switch 8 is mounted in the housing of the apparatus and has anactuator including first part 8a having a slot, a second part 10carrying a coupling pin 11 passing through a slot 3b in the end portionof locking bar 3, a pair of washers 12 and 13 mounted on pin 11 onopposite sides of locking bar 3 and slot 3a, and an adjustment screw 9which is threaded into part 10 and secures the same with coupling pin 11to part 8a, permitting adjustment of the length of the actuator and ofthe position of coupling pin 11 in relation to locking bar 3 and itsslot 3b.

Slot 3b has a first elongated circular part permitting turning movementof the actuator with coupling pin 11 between the positions shown inFIGS. 1 and 2 while locking bar 3 remains in the same position. Thismovement is controlled by a manually operated member 7 which has adownwardly projecting operating member 7a having a lower forked endforming an open slot 7b in which a portion of coupling pin 11 islocated.

In the positions shown in FIGS. 1 and 2, the typewriter is in anoperative condition, and closure 5 is closed. The manually operatedmember 7 can be shifted from the position of FIG. 1 in which couplingpin 11 is located at one end of slot 3b and switch 8 is in its circuitbreaking position, to the position of FIG. 2 in which coupling pin 11 islocated at the other end of slot 3b and the actuator 8a, 10, 11 isshifted to place the switch in the circuit making position.

As best seen in FIG. 1, slot 6b has a locking slot portion at one endwhich extends transverse to the direction of slot 3b. When closure 5 isopened, and locking bar 3 moves to the end position shown in FIG. 3,coupling pin 11 is located in the region of the transverse slot portion3d so that the above-described pivotal movement of locking bar 3 to theposition of FIG. 3 located in slot or cutout 60 is possible due to thefact that coupling pin 11 enters the portion 3d. Since pin 11 is locatedin slot portion 3d, the actuator 8a, 10, 11 cannot turn relative tolocking bar 3 which is locked by the edge 6d of cutout 6c.

Operation In the normal operative position of the typewriter shown inFIGS. 1 and 2, the closed closure 5 holds locking bar 3 against theaction of spring 4 by engaging projection 30. Assuming that switch 8 isin the circuit breaking position shown in FIG. 1, coupling pin 11 islocated at the left end of coupling slot 3b, and it is possible to shiftswitch 8 to the circuit making position in which coupling pin 11 islocated at the right end of slot 3b and in the region of the lockingslot portion 30, as shown in FIG. 2.

Assuming that the switch is in the circuit breaking position shown inFIG. 1, and closure or top cover 5 is opened for cleaning the types orexchanging the ribbon, locking bar 3 follows the upward movement ofclosure 5 under the action of spring 4 until the lower end of guide slot3a abuts pivot means 2, as shown in FIG. 3. The movement of locking bar3 is rearward and upward due to the position of guide slot 3a. Whenduring this movement of locking bar 3, coupling pin 11 arrives at theright end of guide slot 3b, locking bar 3 is turned about pivot 2 byspring 4 to the locking position shown in FIG. 3 which is possible dueto the fact that the end of locking bar 3 is now located rearwardly ofthe edge 6d of slot or cutout 6c, and furthermore due to the fact thatlocking slot portion 3d is now aligned with coupling pin 11. In theposition of FIG. 3, locking bar 3 is locked against movement to the leftand to the right, and locking slot portion 3d locks coupling pin 11 andthe actuator against turning movement to' the circuit making position.

When closure 5 is again closed, it engages first projection 30 anddisplaces the same downward so that locking bar 3 is first turned aboutpivot 2 in clockwise direction until its end moves out of slot or cutout6c, and coupling pin 11 is again located in the coupling slot 3b.Further downward movement of closure 5 displaces projection 30 so thatlocking bar 3 is moved in longitudinal direction toward the right asviewed in FIG. 3 with guide slot 3a moving along the stationary pivot 2,and the end portion of locking bar 3 sliding on the bottom face of coverplate 6 to the position of FIG. 1. The position of the manually operatedmember 7, and the circuit breaking position of the switch are notchanged.

If the manually operated member 7 is in the position of FIG. 2, holdingthe actuator 8a to 11 in the position in which switch 8 closes thecircuit of the typewriter, and closure 5 is opened, spring 4 urgeslocking bar 3 to move to the left as viewed in FIG. 2 and to turn incounterclockwise direction. As long as the end portion of locking bar 3slides on the bottom face of cover plate 6, locking bar 3 moves rearwardand upward under the action of spring 4 toward the left, displacingcoupling pin 11 to the left, since coupling pin 11 abuts the end ofcoupling slot 3b. In this manner, actuator 8a, 10, 11 is turned from thecircuit making position of FIG. 2 to the circuit breaking position, andwhen the end of locking bar 3 reaches the edge 6d ofslot or cutout 6c,spring 4 turns locking bar 3 about pivot 2 so that locking slot portion3d receives coupling pin 11 and locks the same together with the switchactuator to hold the switch in the circuit breaking position. Themanually operable member 7 is shifted by the coupling pin 11 which islocated in slot 7b of operating member 7a. When closure 5 is fullyopened, the position of FIG. 3 is again obtained, with the switch lockedin the circuit breaking position.

When closure 5 is closed again, projection 30 is engaged, and lockingbar 3 turned in clockwise direction out of slot 6c while coupling pin 11assumes a position located at the end of the longitudinal coupling slot60. Further downward movement of closure 5 displaces locking bar 3 tothe right until the position of FIG. 1 is again obtained, the manuallyoperable member 7 and the switch remaining in the circuit breakingposition until shifted by the operator.

From the above description of an embodiment of the invention, it willbecome apparent that coupling slot 3]) and coupling pin 11 constitute alost motion coupling means for coupling locking bar 3 in the position ofFIGS. 1 and 2 to the switch actuator for movement toward the left tofollow closure 5 toward the open position. The lost motion couplingmeans 11, 3b permit shifting of the actuator from the circuit breakingposition of FIG. 1 to the circuit making position of FIG. 2 by operationof the manually operated member 7. Spring 4 is a biasing means formoving locking bar 3 in longitudinal direction together with the closure5, and for turning the locking bar in a transverse direction to placecoupling pin 11 in the locking slot portion 3d in the locking positionof locking bar 3 shown in FIG. 3.

It will be understood that each of the elements described above, or twoor more together, may also find a useful application in other types ofsafety switch locks ditferingfrom the types described above.

While the invention has been illustrated and described as embodied in asafety switch lock for a typewriter for automatically shifting a switchto a circuit breaking position when a closure of a housing is opened,and for locking the switch in circuit breaking position as long as theclosure is open, it is not intended to be limited to the details shown,since various modifications and structural changes may be made withoutdeparting in any way from the spirit of the present invention.

Without further analysis, the foregoing will so fully reveal the gist ofthe present invention that others can by applying current knowledgereadily adapt it for various applications without omitting featuresthat, from the standpoint of prior art, fairly constitute essentialcharacteristics of the generic or specific aspects of this inventionand, therefore, such adaptations should and are intended to becomprehended within the meaning and range of equivalence of thefollowing claims.

What is claimed as new and desired to be protected by Letters Patent isset forth in the appended claims.

We claim:

1. Safety switch lock, comprising, a casing having closure means movablebetween a first closed position and a second open position; switch meansmounted on said housing and having an actuator movable between a firstcircuit making position and a second circuit breaking position; lockingmeans connected with said closure means for movement therewith and beinga first position when said closure means is in said first position andbeing in a second position when said closure means is in said secondpostion, said locking means having lost motion coupling means connectedwith said actuator so that the same remains in said second positionthereof when said locking means and closure means move to said secondpositions of the same, and so that said actuator in said first positionis coupled with said locking means in said first positon of the same andmoves to said second position when said locking means moves to saidsecond positions; and biasing means for urging said locking means to alocking position locking said actuator when said locking means and saidactuator are both in said second positions so that said actuator islocked in said circuit breaking position when said closure is in saidopen position.

2. Safety switch lock as claimed in claim 1 comprising mounting meansmounting said locking means on said housing for movement in onedirection between said first and second positions, and for turningmovement in a direction transverse to said one direction between saidsecond and locking positions.

3. Safety switch lock as claimed in claim 2 wherein said mounting meansinclude pivot means secured to said casing, and wherein said lockingmeans has a guide slot receiving said pivot means; and wherein saidbiasing means urges said locking means into engagement with said closuremeans so that said locking means in said first position follows saidclosure means to said second open position and assumes said secondposition thereof.

4. Safety switch lock as claimed in claim 3 wherein said locking meanshas a portion engaging said closure means in said first closed position;and wherein said biasing means includes a spring secured to said housingand to said locking means and urging said locking means to said secondand locking positions of the same.

5. Safety switch lock as claimed in claim 1 wherein said lost motioncoupling means includes a coupling pin on said actuator and couplingslot in said locking means slidably receiving said coupling pin, saidcoupling pin being located at first and second ends, respectively, ofsaid coupling slot when said locking means is in said first position,and said actuator is in said first and second positions, respectively,said second end of said coupling slot having a transverse locking slotportion; and wherein said biasing means urge said locking means in saidsecond position to move with said locking slot portion to said lockingposition in which said coupling pin of said actuator in said secondposition is located in said locking slot portion and is locked with saidactuator so that the same cannot be moved to said first circuit makingposition.

6. Safety switch lock as claimed in claim 1 wherein said casing is apart of an electric typewriter, and wherein said closure means is thetop cover of the typewriter.

7. Safety switch lock as claimed in claim 1 wherein said switch meansincludes a manually operable member connected with said actuator formovement therewith and being shifted when said actuator is shiftedbetween said circuit breaking and circuit making positions.

8. Safety switch lock as claimed in claim 1 wherein said biasing meansurges said locking means to move to said second position, and from saidsecond position to said locking position; and wherein said locking meansabuts said casing in said first position and is released by said casingin said second position for movement to said locking position.

9. Safety switch lock as claimed in claim 1 wherein said locking meansis a locking bar having a guide slot, and a coupling slot with atransverse locking slot portion; comprising a pivot means on said casinglocated in said guide slot; wherein said biasing means is a springconnecting said locking bar with said casing and urging said locking barto follow said closure means to said second open position, and to turnto said locking position; wherein said actuator has a coupling pinlocated in said coupling slot and forming with the same said lost motioncoupling means, said coupling pin being located in said locking slotportion in said locking position of said locking bar; wherein saidlocking bar has an end portion sliding on said casing in said firstposition and being released by the same in said second position to abuta casing portion whereby movement of said locking bar in said lockingposition to said first position is blocked so that movement of saidactuator to said first position of the same is blocked.

10. Safety switch lock as claimed in claim 9 wherein said switch meansincludes a manually operable member connected with said actuator formovement with the same.

No references cited.

ROBERRT K. SCHAEFER, Primary Examiner.

I. R. SCOTT, Assistant Examiner.

